Surging Republican presidential hopeful Rick Santorum has gone from a man of modest income to millionaire since losing his U.S. Senate seat in 2006, earning much of it by working as a conservative commentator on Fox News and advising industry and lobby firms.

Santorum earned $1.3 million in 2010 and the first half of 2011, according to his most recent financial disclosure form. The largest chunk of his employment earnings — $332,000 — came from his work as a consultant for groups advocating and lobbying for industry interests. That included $142,500 to help advise a Pennsylvania natural gas firm, Consol Energy, and $65,000 to consult with lobby firm American Continental Group, and its insurance services client.

In his role as a social conservative commentator and speaker, Santorum received $239,000 as a news contributor on Fox News, and another $217,000 as a senior fellow at the conservative Ethics and Public Policy Center. There he wrote numerous articles and worked on the center’s Program to Protect America’s Freedom, an effort to focus attention on violations on religious liberty in foreign countries. He also received $83,999 as a talk show host for Salem Radio, based in Camarillo, Calif.

Santorum spokesman Hogan Gidley said he planned to provide comment from the campaign shortly.

Santorum also earned sizable amounts in director’s fees and stock options, a total of $395,414. That came from his service on the board of Universal Health Services, where he was appointed after his 2006 Senate loss to Democratic challenger Bob Casey.

Santorum formally announced his bid as a Republican candidate for president in June and remained for months in the bottom rankings in the wide field of contenders. But the conservative former member of House Republican leadership surged ahead in the Iowa caucuses, winning second place just behind first-place finisher Mitt Romney.

On Thursday morning, Bloomberg News posted an online article about his financial disclosure form, filed in October, and the rise in Santorum’s income since his departure from office.